Abstract: The invention relates to a seismic acquisition process where the streamers are intentionally directed to follow an oscillating sweep pattern behind a tow vessel to counteract the effect of the large gaps between the streamers while acquire a wide sweep of data through each pass over the survey area.

Abstract: A method and a marine towing system for towing streamers or sources. The towing system includes a connecting line; a first paravane connected to the connecting line, wherein the connecting line is configured to connect the first paravane to a vessel; a spur line connected to the first paravane and configured to provide a tension to maintain streamers apart from each other; and a second paravane connected to the connecting line, between the first paravane and the vessel. The second paravane is configured to increase an angle (?4) between the connecting line and the spur line.

Abstract: Depth and tilt control systems for geophysical sensor streamers and methods of use are discussed. Such systems may include a plurality of tilt sensors disposed at spaced apart locations along the geophysical sensor streamer, each tilt sensor having a first tilt sensing element arranged to measure tilt of the geophysical sensor streamer proximate the associated spaced apart location, a plurality of LFD control devices, each disposed proximate one of the tilt sensors along the geophysical sensor streamer, and a plurality of microcontrollers, each microcontroller in signal communication with at least one of the LFD control devices and its associated tilt sensor, wherein each microcontroller is capable of utilizing the tilt measured by the associated tilt sensor to selectively operate the associated LFD control device to cause the geophysical sensor streamer to align with a selected depth profile.

Abstract: In a first embodiment the invention comprises a method for gathering geophysical data, including towing geophysical data gathering equipment behind a survey vessel in a body of water, said equipment including an array of sensor streamers extending behind said vessel, and determining a geodetic location of a streamer steering reference point at a forward end of the sensor streamers and a reference direction. At least one sensor streamer included in said array of sensor streamers is laterally deflected in response to the determined geodetic location of said streamer steering reference point and the determined reference direction.

Abstract: Disclosed are methods and systems for controlling spread and/or depth in a geophysical survey. An embodiment discloses a method for geophysical surveying, comprising: towing two streamers laterally spaced apart through a body of water at a depth of at least about 25 meters, each of the streamers comprising geophysical sensors disposed thereon at spaced apart locations; maintaining lateral separation of at least about 150 meters between the two streamers using at least two submersible deflectors, the two submersible deflectors being individually coupled to one of the two streamers; and detecting signals using the two geophysical sensors while the two streamers are towed at the depth of at least about 25 meters.

Abstract: A method for towing a streamer array includes moving a vessel along a body of water. Streamers are towed by vessel. A relative position is determined at selected points along each streamer with respect to the vessel. At least one of the streamers is deflected at least one longitudinal position along the streamer in response to the determined positions to maintain the streamers in a selected geometry. The selected geometry is related to one of survey vessel heading, energy source trajectory, previously plotted sensor trajectory and a lateral separation related to distance from the towing vessel.

Abstract: This disclosure is related to the field of streamers. In one embodiment, a streamer may include a group of particle motion sensors. In some embodiments, at least two of the particle motion sensors in the group are movable relative to one another within the streamer, and the two particle motion sensors are configured to measure motion along a particular axis. In some embodiments, the streamer may additionally include a plurality of pressure sensors.

Abstract: An inventive method provides for control of a seismic survey spread while conducting a seismic survey, the spread having a vessel, a plurality of spread control elements, a plurality of navigation nodes, and a plurality of sources and receivers. The method includes the step of collecting input data, including navigation data for the navigation nodes, operating states from sensors associated with the spread control elements, environmental data for the survey, and survey design data. The positions of the sources and receivers are estimated using the navigation data, the operating states, and the environmental data. Optimum tracks for the sources and receivers are determined using the position estimates and a portion of the input data that includes at least the survey design data. Drive commands are calculated for at least two of the spread control elements using the determined optimum tracks. The inventive method is complemented by an inventive system.

Abstract: Variable depth multicomponent sensor streamer. At least some of example embodiments are methods including designing a depth profile for first portion of a sensor streamer by determining a first target depth for a first hydrophone-geophone pair, the first hydrophone-geophone pair at a first offset along the sensor streamer, the determining based on a first projected geophone noise floor at the first offset and a first expected spectral notch of a hydrophone of the first hydrophone-geophone pair; and determining a second target depth for a second hydrophone-geophone pair, the second hydrophone-geophone pair at a second offset along the sensor streamer, the second offset greater than the first offset, and determining the second target depth based on a second projected geophone noise floor in the sensor streamer at the second offset and a second expected spectral notch of a hydrophone of the second hydrophone-geophone pair; wherein the second target depth is greater than the first target depth.

Abstract: There is a method for obtaining control of a source array configured to generate seismic waves. The method includes accessing an interface unit attached to a fixed structure that is substantially stationary in water, the interface unit being connected to a source array; entering a passcode to the interface unit to gain access to the source array; downloading a shooting sequence or a driving signal to a controller of the source array; and actuating the source array to generate seismic energy into water.

Abstract: A method for determining a sail plan for a towed-array marine seismic survey includes: dividing a survey area into a regular grid of tiles; and identifying a subset of the tiles as nodes around which continuously curved sail lines are defined. The nodes define regular pattern further including: a first subpattern of nodes; and a second subpattern of nodes offset from the first subpattern. A method for conducting a towed array marine survey includes: traversing a plurality of continuously curved sail lines across a survey area, each sail line being relative to a node; and acquiring seismic data while traversing the continuously curved sail lines. The set of nodes defining a regular pattern further including: a first subpattern of nodes; and a second subpattern of nodes offset from the first subpattern.

Abstract: A control system for use in a marine seismic survey is provided. The system may include one or more processors configured to receive a desired position for one or more seismic streamers during the marine seismic survey. The one or more processors may be further configured to determine a current position for the one or more seismic streamers and to adjust a position of a steering device on each streamer, based upon, at least in part, a comparison between the current position of the one or more seismic streamers and the desired position of the one or more seismic streamers.

Abstract: A marine acoustic source system for generating an acoustic wave in a body of water. The marine acoustic source system includes a first marine acoustic source array having first and second external source sub-arrays, each sub-array including one or more individual source elements; a first actuator device connected to the first external source sub-array; and a first rope connecting the first actuator device to a first lead-in that is configured to connect to a head of a streamer. The first actuator device is configured to control a length of the first rope in order to control a position of the first source array relative to the streamer.

Abstract: Method and marine acoustic source array for generating an acoustic wave in a body of water. The marine acoustic source array includes first and second external source sub-arrays, each sub-array including one or more individual source elements; a first actuator device connected to the first external source sub-array; and a second actuator device connected to the second external source sub-array. The first actuator device has a corresponding cable configured to connect to a first lead-in, and the second actuator device has a corresponding cable configured to connect to a second lead-in such that a position of the source array as a whole is controllable along a line substantially perpendicular to a path of the source array.

Abstract: Disposable antifouling covers for geophysical survey equipment. At least of example embodiments are methods including deploying marine geophysical survey equipment. The deploying may include: installing a disposable antifouling cover of plastic material on a portion of the marine geophysical survey equipment, wherein the disposable antifouling cover occludes a majority of an exterior surface of the portion of the marine geophysical survey equipment; and placing the marine geophysical survey equipment in a body of water.

Abstract: Method and marine acoustic source array for generating an acoustic wave in a body of water. The marine acoustic source array includes first and second external source sub-arrays, each sub-array including one or more individual source elements; a first actuator device connected to the first external source sub-array; and a second actuator device connected to the second external source sub-array. The first actuator device has a corresponding cable configured to connect to a first lead-in, and the second actuator device has a corresponding cable configured to connect to a second lead-in such that a position of the source array as a whole is controllable along a line substantially perpendicular to a path of the source array.

Abstract: Method and system for improving offset/azimuth distribution. The system includes plural streamers towed by a streamer vessel; a central source towed by the streamer vessel; first and second front sources located in front of the plural streamers along a traveling direction of the streamer vessel; and first and second large offset front sources located in front of the first and second front sources along the traveling direction. The offset distance between the first and second large offset front sources, along a cross-line direction, is larger than an offset distance between the first and second front sources.

Abstract: A method of assisting the deployment/retrieval of linear acoustic antennas towed by a vessel, said linear antennas each having geophysical data sensors, means for measuring the distance of at least one adjacent linear antenna, during the course of which at least one of said linear acoustic antennas has at least longitudinal mobility in relation to said vessel, including: at least one phase for configuring cells (Cn) each defined by a central position corresponding to a distance-measuring means (T), and by at least one peripheral position corresponding to another distance-measuring means (T) in proximity to said distance-measuring means (T) for said central position, reference distances between said central positions and said peripheral positions being predetermined; and at least one phase for controlling said central and peripheral positions with respect to said reference distances, by establishing communication between at least some of said distance-measuring means (T).

Abstract: A method of acoustic positioning determination includes detecting a temperature gradient profile across a depth of water, determining a level of a thermal boundary between an upper temperature level and a lower temperature level, and determining a distance from the thermal boundary to position the acoustic positioning device and positioning the acoustic positioning device at that location.

Abstract: The invention relates to a source device for the emission of seismic waves designed to operate by being towed by a vessel. The source device according to the invention comprises at least three support-beams, a plurality of guns placed along each support-beam, a central hub receiving one end of support-beams and arranged such that support-beams can be deployed according to a star-like geometry, and the means to keep support-beams in this geometry during operation.

Abstract: Marine seismic streamer steering apparatus are described having an elongate body, at least a portion of which is positioned eccentric of a marine seismic streamer, the apparatus having stability features selected from: one or more lateral steering control surfaces providing a center of lift approximately through a vertical streamer axis; one or more buoyancy elements providing a center of buoyancy through the same or a different vertical axis approximately through the center of the streamer; and combinations thereof. The apparatus have improved stability and avoid heeling during use.

Abstract: An autonomous underwater vehicle (AUV) for recording seismic signals during a marine seismic survey. The AUV includes a body having a base and sides; a propulsion system for guiding the AUV to a final target on the ocean bottom; a pump-jet connected to an inlet and plural base outlets, wherein the plural base outlets are distributed on the base; a processor connected to the pump-jet and configured to activate the pump-jet when the base in on the ocean bottom; and a seismic sensor configured to record seismic signals. The pump-jet has a first low speed so that water jets expelled at the plural base outlets fluidize the ocean bottom underneath the base and buries the AUV.

Abstract: Method and system for improving offset/azimuth distribution. The system includes plural streamers towed by a streamer vessel; a central source towed by the streamer vessel; first and second front sources located in front of the plural streamers along a traveling direction of the streamer vessel; and first and second large offset front sources located in front of the first and second front sources along the traveling direction. The offset distance between the first and second large offset front sources, along a cross-line direction, is larger than an offset distance between the first and second front sources.

Abstract: There is described an apparatus and method for deploying a sensor array comprising a plurality of sensors (5) joined together by connection cables (6) in one or more “chains”, and connected to an input/output device (8). An input/output connection unit (7, 15) is provided on a carrier (10), and the sensors are held on or in deployment devices (14a-14e) mounted to the carrier with their connection cables (6) connected to the input/output connection unit (7, 15). The input/output device (8) may also be mounted to the carrier, and connected to the connection unit (7, 15). The carrier (10), sensors, and input/output device (8) may be delivered as a single package to the area where the sensor array is to be deployed. The sensors are then moved from the carrier to their final positions. The deployment devices (14a-14e) may be detached from the carrier and moved sequentially to the sensor positions, and a sensor may be removed from the deployment device at each sensor position.

Abstract: In the field of marine geophysical surveying, systems and methods for controlling the spatial distribution or orientation of a geophysical sensor streamer or an array of geophysical sensor streamers towed behind a survey vessel are provided. Various techniques for changing the spatial distribution or orientation of such geophysical sensor streamers in response to changing conditions are provided. For example, crosscurrent conditions may be determined based on configuration data received from positioning devices along the length of a streamer, and a new desired orientation for the streamer may be determined based on the crosscurrent conditions. The new desired orientation may include a new desired feather angle for the streamer.

Abstract: Techniques are disclosed relating to reducing drag on cables towed behind a vessel in a body of water. In one embodiment, an apparatus includes a signal source coupled to a survey vessel via a source cable, and the source cable includes a plurality of floats along its length. The floats may in some embodiments allow the source cable to be lifted partially, substantially, or entirely above the surface of the water. Lifting the cable above the surface of the water may in turn decrease the amount of hydrodynamic drag on the cable, reducing the force necessary (e.g., from lateral deflectors on the cable or at the signal source) to tow the source and/or the force necessary to attain a desired lateral position for the signal source. The disclosed techniques may in some embodiments be used to tow such sources at relatively wide lateral separations.

Abstract: A foil having a leading edge, trailing edge, chord and span is attached between a first head float position and bottom submerged position below the head float on the array. The foil being flexible along its span and has a first interior conduit rearward of the leading edge and a second interior conduit forward of the trailing edge. The conduits are centered on the chord and separated by a distance. A first cable having a first length is strung inside the first conduit and a second cable having a second length is strung inside the second conduit, and an adjustment mechanism is used to vary the length of the first cable relative to the length of the second cable and vice versa.

Abstract: An inventive method provides for control of a seismic survey spread while conducting a seismic survey, the spread having a vessel, a plurality of spread control elements, a plurality of navigation nodes, and a plurality of sources and receivers. The method includes the step of collecting input data, including navigation data for the navigation nodes, operating states from sensors associated with the spread control elements, environmental data for the survey, and survey design data. The positions of the sources and receivers are estimated using the navigation data, the operating states, and the environmental data. Optimum tracks for the sources and receivers are determined using the position estimates and a portion of the input data that includes at least the survey design data. Drive commands are calculated for at least two of the spread control elements using the determined optimum tracks. The inventive method is complemented by an inventive system.

Abstract: A far-field detection apparatus for measuring a far-field signature of a seismic source includes a main tow cable, a depth control device, sensor lines, at least two deflectors and seismic sensors. The depth control device is attached to the main tow cable. Each of the sensor lines has a first end attached to the main tow cable. Each of the deflectors is attached to a second end of the sensor lines, respectively. The deflectors are configured to generate forces pulling the sensor lines away from the main tow cable. The seismic sensors are attached between the first end and the second end of each of the sensor lines. The seismic sensors are configured to measure seismic waves generated by the seismic source.

Abstract: A source array generates seismic waves in water during a marine seismic survey. The source array includes a first sub-array including plural source elements; plural acoustic transceivers distributed along the first sub-array; a positioning system; a primary position control device configured to control a position of the first sub-array; and a secondary position control system configured to adjust a depth of the first sub-array.

Abstract: A compound buoy. At least some of the illustrative embodiments are buoy systems that include: a surface buoy; a subsurface buoy comprising an elongated outer body; a connector disposed on the lower surface; and a winch having a line, the line coupled between the surface buoy and the subsurface buoy. The buoy system has first configuration in which the upper surface of the subsurface buoy abuts the surface buoy, the abutting relationship held by tension in the line, and the buoy system has a second configuration where a distance between the surface buoy and the subsurface is limited by a length of the line spooled off the winch. In operation, the subsurface buoy supports more of the subsurface load than the surface buoy.

Abstract: A method of deploying a device to the seabed with a submersible vehicle, the vehicle having a hull which defines a hull axis and appears substantially annular when viewed along the hull axis. The hull has an interior defining a duct which is open at both ends. The device is mounted to the hull on one or more struts so that it is positioned in line with the duct or at least partially within the duct. The device is transported to the seabed mounted to the hull on the strut(s), water flowing through the duct as it does so. The device is then deployed on the seabed after it has been transported to the seabed by the vehicle.

Abstract: Disclosed are methods and apparatus for adaptive source electromagnetic (EM) surveying. In accordance with one embodiment, a source waveform signal is generated, and an outgoing EM signal which is based on the source waveform signal is transmitted using an antenna. A responsive electromagnetic signal is detected using at least one electromagnetic sensor, and a receiver waveform signal based on the responsive electromagnetic signal is obtained. A feedback control signal which depends on at least one input signal is determined. Based on the feedback control signal, the source waveform signal is adapted. Other embodiments, aspects, and features are also disclosed.

Abstract: Apparatus, computer instructions and method for processing seismic data related to a subsurface of a body of water. The method includes inputting data indicative of recordings made by detectors provided on a curved profile in response to an acoustic wave reflected from the subsurface; applying a matched mirror migration procedure to the data, where (i) actual positions of the detectors on the curved profile and corresponding recordings, and (ii) fictitious mirror positions of the actual detectors on the curved profile and corresponding recordings with a changed sign are added in the matched mirror migration; and generating a final image of the subsurface based on the matched mirror migration procedure.

Abstract: A marine seismic system having a tow vessel; a first tow member connected to the tow vessel; a second tow member connected to the tow vessel; a first distance member having a first end connected to the first tow member and a second end connected to the second tow member; and a first attachment device connecting the first end to the first tow member, the first attachment member operational between an engaged position securing the first end of the distance member in a fixed position relative to the first tow member and a disengaged position permitting the first attachment device to move along a portion of the first tow member.

Abstract: In a first embodiment the invention comprises a method for gathering geophysical data, including towing geophysical data gathering equipment behind a survey vessel in a body of water, said equipment including an array of sensor streamers extending behind said vessel, and determining a geodetic location of a streamer steering reference point at a forward end of the sensor streamers and a reference direction. At least one sensor streamer included in said array of sensor streamers is laterally deflected in response to the determined geodetic location of said streamer steering reference point and the determined reference direction.

Abstract: Methods related to controlling a source array while performing a seismic survey to achieve an intended source signature. A current three dimensional arrangement of the individual seismic sources is compared with a target 3D arrangement. In view of the comparison, position of at least one of the individual seismic sources is adjusted so that the adjusted 3D arrangement of the individual seismic sources to substantially match the target 3D arrangement.

Abstract: A method and system for deploying seismic tows, such as seismic streamers, from a common carrier rope for conducting marine seismic surveys. The deployment system generally comprises a carrier rope having at least one deflector urging the carrier rope laterally relative to the towing vessel and seismic tows that are independently moveable along the deployed carrier rope to desired locations from which to be deployed. The carrier rope may be deployed from the tow vessel into the water prior to deploying the seismic streamer(s) into the water.

Abstract: A depth-varying marine acoustic source array is configured for generating an acoustic wave in a body of water. The depth-varying marine acoustic source array includes a float; plural source points connected to the float through corresponding cables; and a housing extending from a first source point to a last source point, the housing including plural segments. The at least one segment is configured to withstand bending.

Abstract: The present disclosure generally relates to the use of a self-propelled underwater vehicle for seismic data acquisition. The self-propelled underwater vehicle is adapted to gather seismic data from the seafloor and transmit such data to a control vessel. The self-propelled underwater vehicle may be redeployed to several seafloor locations during a seismic survey. Methods for real-time modeling of a target zone and redeployment of the self-propelled underwater vehicle based on the modeling are also described.

Abstract: The present disclosure generally relates to the use of a self-propelled underwater vehicle for seismic data acquisition. The self-propelled underwater vehicle is adapted to gather seismic data from the seafloor and transmit such data to a control vessel. The self-propelled underwater vehicle may be redeployed to several seafloor locations during a seismic survey. Methods for real-time modeling of a target zone and redeployment of the self-propelled underwater vehicle based on the modeling are also described.

Abstract: Performing a geophysical survey beneath a surface obstruction, or around a fixed object or formation. At least some of the example embodiments include: programming a towing pattern into an autonomous underwater vehicle; and towing a sensor streamer under the surface obstruction, or around the fixed object or formation by the autonomous underwater vehicle. In some of the embodiments, the sensor streamer comprises a distributed sensor in the form of an optical fiber. In some of the embodiments, the optical fiber is encapsulated in an outer covering of resilient material, the resilient material exposed to the water during the towing.

Abstract: Various technologies described herein are directed to a method that includes deploying a plurality of wave gliders in a seismic survey area, where the plurality of wave gliders has one or more seismic sensors coupled thereto for acquiring seismic data. The method may also include deploying at least one source vessel in the seismic survey area, where the at least one source vessel has one or more sources coupled thereto and a central communication unit disposed thereon. The method may then include positioning the plurality of wave gliders according to an initial navigation plan. The method may further include monitoring a relative position of a respective wave glider in the plurality of wave gliders with respect to other wave gliders in the plurality of wave gliders and with respect to the at least one source vessel.

Abstract: A wide-azimuth marine seismic survey system according to one or more aspects of the present disclosure may include a streamer array; a first source towed from a first vessel; a second source towed from a second vessel; and a supplemental offset source towed from the first vessel and the second vessel.

Abstract: A method for towing a streamer array includes moving a vessel along a body of water. Streamers are towed by vessel. A relative position is determined at selected points along each streamer with respect to the vessel. At least one of the streamers is deflected at least one longitudinal position along the streamer in response to the determined positions to maintain the streamers in a selected geometry. The selected geometry is related to one of survey vessel heading, energy source trajectory, previously plotted sensor trajectory and a lateral separation related to distance from the towing vessel.

Abstract: An autonomous underwater vehicle (AUV) is configured to record seismic signals during a marine seismic survey. The AUV includes a body having a base (B) and first and second sides (A, C), the body having a head part and a tail part; a propulsion system for guiding the AUV to a final target on the ocean bottom; jet pumps connected to corresponding nozzles on the first and second sides (A, C); a control device connected to the jet pumps; and a seismic sensor configured to record seismic signals. The jet pumps are actuated by the control device in a given sequence so that the base (B) penetrates into the ocean bottom.

Abstract: Techniques are disclosed relating to steering a signal source towed behind a survey vessel. In one embodiment, a method includes towing a signal source and a streamer in a body of water. The signal source includes a steering mechanism. The method further includes determining a current heading of the streamer and, based on the determined heading, using the steering mechanism to adjust a heading of the signal source. In some embodiments, the method also includes determining a current heading of the signal source based on location information received from one or more location buoys coupled to the signal source, and, based on the determined heading of the signal source, using the steering mechanism to adjust the heading of the signal source. In one embodiment, the steering mechanism is used to align the heading of the signal source with the heading of the streamer.

Abstract: A method for towing a marine seismic acquisition array in a body of water includes towing a plurality of laterally spaced apart sensor streamers behind a survey vessel in the water. A lateral spacing between adjacent streamers is represented by L. At least two laterally spaced apart seismic energy sources are towed behind the survey vessel. A lateral spacing between the at least two sources is represented by kL, wherein k is a constant and wherein k is at most equal to the number of streamers.

Abstract: A survey method includes towing one or more sources and one or more streamers behind a vessel to acquire geophysical survey data. Steering signals are determined for at least one of: the one or more sources, the one or more streamers, and the vessel. The steering signals minimize an error function having parameters that include a measure of a cross-line position error and a measure of data quality. The cross-line position error may be measured as an offset of the sources or the receivers from their desired paths, or in some embodiments as an offset between midpoints for base survey traces and subsequent survey traces. Some embodiments may employ a maximum spatial cross-correlation coefficient between a newly acquired trace and one or more base survey traces as a data quality measure, while others may employ a time shift, a phase rotation, or a normalized root mean square error. Data quality may indicate sensor noise levels.

Abstract: The present disclosure generally relates to the use of a self-propelled underwater vehicle for seismic data acquisition. The self-propelled underwater vehicle is adapted to gather seismic data from the seafloor and transmit such data to a control vessel. The self-propelled underwater vehicle may be redeployed to several seafloor locations during a seismic survey. Methods for real-time modeling of a target zone and redeployment of the self-propelled underwater vehicle based on the modeling are also described.